Developments in miniaturization and large-scale integration in fluidics have led to the concept of creating an entire chemistry or biology laboratory on a fluidic analog of the electronic microchip. Such integrated microfluidic devices (known as Micro Total Analysis Systems, or μTAS) are seen as key to automating and reducing costs in many biological analysis applications, including genetic analyses and medical diagnostics. When conducting such biological analyses, however, it is often important to avoid the possibility of cross-contamination between separate samples. For example, if the same instrument is used for analyzing a series of blood samples from separate patients, it is considered completely unacceptable for any residue from one sample to remain in the instrument where it might contaminate a later sample. This has led to the design of instruments where all components that may come into contact with the sample are removable, and are either disposed of or cleaned.
A microfluidic device should be fully capable of manipulating multiple fluids. Manipulation includes a number of functions such as storage, transport, heating, cooling, and mixing. Performing these functions requires that the microfluidic device include not only flow channels, but also at least valves, pumps, heaters, and coolers. Although all these functions have been demonstrated with varying degrees of success on microfluidic devices, valves and pumps have typically been complex devices, which are difficult to manufacture. Unfortunately, this leads to high fabrication costs, which generally make it impractical to manufacture the devices to be disposable.
Thus, a need exists for a microfluidic device that is capable of performing various manipulations on fluids while also being manufacturable in a manner suitable for the devices to be disposable.